Cos x=1/7 Cos(x+y)=-11/14 x y 为锐角,求Cos y
已知cos(x)=1/7 cos(x+y)=-11/14 且x,y属于(0,90) 求cos(y)
) y=cos(x-y)
Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y)
sin(x+y)sin(x-y)=k,求cos^2x-cos^2y
证明COS(X+Y)COS(X-Y)=COS^2X-SIN^2Y
求y=cos|x|的图像.
cos(x+y)+y=1 求dy/dx
最近没有认真听数学已知x,y为锐角,cos(x+y)=12/13,cos(2x+y)=3/5,则cosx的值为?
y =(cos^2) x - sin (3^x),求y'
已知x,y为锐角,且满足cos x=45,cos(x+y)=35,则sin y的值是( )
y=(1+x^4)^cos x,求dy
Matlab编程问题 cos(x*y)*cos(x*(1-y))-0.5x*sin(x*y)*sin(x*(1-y))=